Work

Bi-analyte demonstration of non-resonant, single-molecule SERS with isolated lithographic enhancement structures

Year: 2026

Type: article

Abstract: Single molecule Raman spectroscopy using isolated, circular ~ 110 nm diameter, multilayer disk enhancement structures fabricated with 355 nm interferometric lithography in a 2D 400 nm period array is reported. Adenine and cytosine are selected as a bi-analyte pair, with comparable strength Raman lines arising from ring breathing modes in proximity (A: 743 cm -1 shift and C: 807 cm -1 shift). Samples are soaked in 1:2 A:C mixtures diluted in water to ~ 1x10 -3 to 5x10 -4 of a monolayer coverage. Raman spectra are obtained with 633 nm excitation. The spectra show Poisson statistics with individual spectra showing: only A; only C; and A & C features demonstrating single molecule sensitivity. Over 90% of the spectra are null spectra without either A or C features. Importantly, the enhancement structures are isolated from each other, no close approach is required as in the case of spherical nanoparticles where ~ 1 nm gap modes are responsible for the large enhancement required for non-resonant single molecule sensitivity.

Source: Scientific Reports

DOI: 10.1038/s41598-026-48456-9

Authors: Xin Jin, Hui Xia, S. R. J. Brueck

Language: English

Topic: Gold and Silver Nanoparticles Synthesis and Applications

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,690

Funder: National Institutes of Health

Award: G9000036416